When an earthquake occurs, the more time people have to respond, the fewer will be the number of people who are injured. Earthquake alarms serve the purpose of sensing motion of the earth's surface and warning those nearby of that motion. Many elaborate and sophisticated seismic measuring devices exist, but are unfortunately not affordable for most people.
There has been a need for an inexpensive earthquake alarm that is effective. Many of the proposed solutions to this need are machines which must remain ready over long periods of time without sounding but need to be reliably functional when an earthquake occurs. The alarms are needed by a wide variety of people who all must be able to install, operate and maintain the alarm. Therefore, the alarm should require the least amount of attention and when maintenance is necessary, it should be simple.
Alarms which have been described in U.S. Pat. Nos. 4,689,997, 4,364,033, 3,990,039 and 1,625,625, have a pendulum body which is moved by the motion of the earth's surface. The pendulum's motion results in producing a signal warning people of the earthquake. These types of alarms suffer from being too insensitive to the earth's motion. Alarms which are sensitive enough are too difficult to set up and maintain due to their sensitivity. Another alarm, which is disclosed in U.S. Pat. No. 4,086,807, has a ball that is magnetically held in place which is moved out of place by the earthquake, sounding an alarm.
There is a need for a simply functioning earthquake alarm that is sensitive to earthquakes and yet is easy to install, operate and maintain. The alarm should also remain Operable after being dormant for long periods of time, and should require a minimum of attention and maintenance.